1. Field
The present disclosure relates to a visible light sensitive photocatalyst, and in particular, to a visible light sensitive photocatalyst capable of decomposing water, a method of producing the visible light sensitive photocatalyst, and an electrochemical water decomposition cell, a water decomposition system, and an organic material decomposition system, each including the visible light sensitive photocatalyst.
2. Description of the Related Art
When a photocatalyst receives light having an energy level equal to or greater than a band gap energy, electrons are excited from a valence band to a conduction band, and thus electrons are disposed in the conduction band and holes are formed in the valence band. The electrons and holes may diffuse to a surface of the photocatalyst and participate in oxidation and reduction reactions.
Photocatalysis is used to directly decompose water using solar energy to generate hydrogen, and is an alternative next-generation energy source. Photocatalysis may also be used to decompose volatile organic compounds (“VOC”s), offensive odors, waste water, decomposable refractory contamination materials, and environmental hormones, and to sterilize germs and bacteria. Accordingly, a photocatalyst technology that uses only solar energy at room temperature is useful for producing hydrogen and for cleaning environments, and photocatalyst technology is receiving attention for use as a powerful method for resolving environmental problems.
Titanium dioxide (TiO2) is used commercially as a photocatalyst, and has excellent organic material and water decomposition characteristics. However, titanium dioxide (TiO2) induces photocatalysis only in response to ultraviolet light, which accounts for about 4% of solar light. Accordingly, to effectively use the photocatalyst technology, there is a need to develop a photocatalyst material having improved visible light activity that effectively uses visible light that accounts for about 43% of solar light.